Current storage vents generally extend until they are flush with the concrete floor, that is they extend to the surface of the concrete floor. When the potatoes or other vegetables are stored or removed vehicles such as trucks are used to store and remove the vegetables. These vehicles may damage and degrade the tops of the vents at about the surface of the concrete floor. At their top the vents fit a slot in the concrete floor typically about 1 inch (about 2½ cm) by 14¼ inches (about 36 cm). At the bottom there is an circular inlet duct, perpendicular to the slot, about 3 inches (about 7½ cm) diameter, the area of the slot is about twice the area of the inlet duct, which allows for about half the outlet slot to be blocked by stored vegetables while air is blown into the storage area. The vent and attached duct are moulded from plastic, typically around ⅛ or 3/16 inch (about 3 or 4½ mm) thick.